The AB line is derived from two lines, A and B, purchased by Streisinger at different times from a pet shop in Albany, Oregon. The original A and B lines probably originated from a hatchery in Florida. Haploid offspring from individual females of the AB line were screened for healthy, good looking embryos, and those females were used to make future generations by crossing them to unselected males. The AB line was maintained in this manner by the Oregon labs from the 1970's to the 1990's. This procedure reduced the number of lethal mutations so that this line can be used for parthenogenesis.By 1991 the AB fish were 70 generations removed from the original wild-type fish that George Streisinger and Charline Walker used to establish the AB line.The *AB (pronounced star-AB) line was derived from the AB line in 1991-1992, using 21 EP (homozygotes produced by the early pressure method) females (no males). These females were selected by Charline Walker from among 180 females on the basis of the phenotype of their haploid embryos. The eggs from these females were subjected to the EP procedure to produce diploid stocks that were kept separate from each other. Each set of progeny was given a separate stock number (S#). These fish were then intercrossed in as many ways as possible. The resulting fish (from six S#s) were used to make the first *AB stock in June of 1992.This stock is currently called AB, instead of *AB, even though it is only distantly related to the original Streisinger AB line. The AB line is currently maintained by a "Round Robin" mating technique: Approximately 60-66 males and 30 females from several different generations are used to make each new generation. Sperm from the males is collected into 6 tubes. An individual's sperm is in only one tube. Eggs are obtained from each of the 30 females. Each clutch is divided and fertilized with sperm from several different tubes. The divided clutches are kept separate from each other. The 15 best looking embryos from each clutch are kept and scored for how many fish survive and produce swim bladders. To be selected for propagating the AB line, 13/15 (86.66%) of the fish must develop swim bladders. Embryos from clutches that pass the swim bladder and survival test are then mixed in equal numbers to form the next AB stock.The ABC line is related to the *AB line but has not been propagated by round robin method. ABC fish have been maintained either by natural crosses or by in-vitro fertilization. Records are available at the University of Oregon Zebrafish Facility for the number of individuals contributing to the stock at each passage and the method used for maintenance at each generation. The number after ABC (e.g., ABC-1, ABC-2, etc.) designates the number of generations the stock is away from *AB. In December 2008, the stock was ABC-6.